Virtualization technologies are currently used for running one or more virtual computers (also called virtual machines (VMs)) on a physical computer. Virtual machines are able to execute an operating system (OS) and application software independently from other virtual machines.
Virtualization software to control a virtual machine is executed on a physical computer. The virtualization software includes items called a hypervisor, management OS, and a management domain. The virtualization software, for example, allocates resources such as processing capacity of a central processing unit (CPU) and memory capacity of a random access memory (RAM) included in a computer to a virtual machine. The OS of each virtual machine controls the application software so that the application software is executed within the scope of the resources allocated to each virtual machine.
In an information processing system that includes a plurality of computers, a virtual machine may be migrated between computers. Migration methods of virtual machines include a method called live migration in which a virtual machine may be migrated without shutting down the OS or application software that is being executed at that time. Information processing between computers may be continued in live migration since the virtualization software copies data (programs may also be included) related to the migrated virtual machine from the memory of the source computer to the memory of the destination computer.
A computer system has been proposed in which, when a power source failure is detected in a certain server connected to an uninterruptible power supply (UPS), the virtual machine running on the certain server is migrated to a failover destination server previously associated with the certain server, and the certain server in which the power failure was detected is shut down.
Japanese Laid-open Patent Publication No. 2009-282714 discloses a related technology.